2007 Exige S Intercooler Air Flow Study

[apk919]

Originally Posted by Thomasio

I'll contribute a window-delete!

Well, here's what I think I've learned from the data I collected on Tuesday:

Streets Of Willow is a relatively short, twisty course. There are only two straightaways of any significant length. If you look at the IAT/EGT graphs above, you can see that thermal equilibrium is clearly reached for the "side scoop open" session, and probably reached at the end of the "side scoop blocked" session. While I was still learning SOW CCW, there is no significant difference in laptimes, corner entry speeds, maximum acceleration, or even spark advance between the two sessions. So my guess is that even though the temps are clearly lower with the additional ducting, heat soak is not a significant factor at SOW. I wish I would've been able to gather data at Buttonwillow 13CW, which has much longer, and closely linked, straight sections.

[apk919]

Originally Posted by Thomasio

Every little bit helps... the thing is, with all of the ducts in the world, if you are sitting in traffic with no airflow your intercooler is heating up. Fans help there where no ducting can. Of course, the better the ducts flow, the faster you will cool your intercooler after you are stuck in traffic and get moving.

I logged an hour of street driving today, and IAT temps were ridiculously lower that those logged for even a tight, twisty road course. Average IAT was 92F, and maximum was 117F... not worth worrying about at all.

EDIT: Ambient temps were about 76F today

[Jack]

Originally Posted by ZJChaser

Jack, post up the photos of your setup in your cup car

Here are a few photos of the famous Aeroman's (aka Brent) creation (he does amazing work ) to increase airflow to the Cup car I/C .... ducts galore.

[apk919]

Originally Posted by Jack

Here are a few photos of the famous Aeroman's creation (he does amazing work ) to increase airflow to the Cup car I/C .... ducts galore.

Next track day, I'll have my data logging hardware set up to plug and play with any Lotus... you should run a logging session with it so we can see how that solution compares...

[shay2nak]

...and remember you guys (Thomas & Andy) are both running different intercoolers.

Originally Posted by Thomasio

Every little bit helps... the thing is, with all of the ducts in the world, if you are sitting in traffic with no airflow your intercooler is heating up. Fans help there where no ducting can. Of course, the better the ducts flow, the faster you will cool your intercooler after you are stuck in traffic and get moving.

That's where I believe a heatshield will help. A lot of air is flowing through the intercooler now, but it's still sitting in an environment which is hot. Mainly heat from under the intercooler. What was your IAT like on that drive?

Originally Posted by apk919

I logged an hour of street driving today, and IAT temps were ridiculously lower that those logged for even a tight, twisty road course. Average IAT was 92F, and maximum was 117F... not worth worrying about at all.

EDIT: Ambient temps were about 76F today

I get the about the same temps with just a fettled S roof. Typically 95-97. I was thinking they would be lower, but 92 is still not bad actually. I was hoping to see around 10* reduction. I hooked up my OBD to my TSX and that has a constant IAT of 87.

[Thomasio]

How did he get thru the rear window? One of those jewel-thief diamond-cutter thingies?!

[Thomasio]

For those who didn't follow the link to my roof setup:

[apk919]

Originally Posted by Thomasio

How did he get thru the rear window? One of those jewel-thief diamond-cutter thingies?!

The rear window on Jack's Cup car is plexiglass, so no fancy glass cutting was necessary...

I do like the idea of having a transparent window in the back (for no good reason other than I like to see the engine compartment), so I suppose it wouldn't be difficult to have a Lexan window fabricated... then let's see: a CF roof scoop suitably modified, more ducting plumbed into the roof duct...

[Thomasio]

Originally Posted by apk919

The rear window on Jack's Cup car is plexiglass, so no fancy glass cutting was necessary...

Ahhh... that makes sense. Looks like a nice install.

[apk919]

Originally Posted by Thomasio

Ahhh... that makes sense. Looks like a nice install.

+1

Very nice and professionally done by Brent (http://www.lotustalk.com/forums/member.php?u=8276)

[Thomasio]

Cutting a hole (actually, two holes) though a perfectly good carbon fiber roof panel.

The foam is used around the perimeter between the two roof cavities to keep the air from wasting energy swirling into the second cavity.

[Jack]

Originally Posted by apk919

+1

Very nice and professionally done by Brent (http://www.lotustalk.com/forums/member.php?u=8276)

Yes, Brent is the best.

He used 3 separate naca ducts and they are rather special (designed to pull and accelerate the air) ... not all naca ducts are created equal. He also had to bond the two layers of the Cup roof together to avoid air loss/escape within the cavities. It was a lot of work. He also modified/fabricated brackets to better position the i/c and aid with heat shielding.

[Thomasio]

Originally Posted by Jack

He also had to bond the two layers of the Cup roof together to avoid air loss/escape within the cavities. It was a lot of work.

That's an important detail. (I used foam for a similar effect, at least until I knew that it worked.)

[shay2nak]

I didn't know you guys are already using heatshields. What does Brent's intercooler look like?

[apk919]

Originally Posted by shay2nak

I didn't know you guys are already using heatshields. What does Brent's intercooler look like?

Don't feel bad; I didn't know until Tuesday either. I need to get my hands on some aluminum stock and make one for myself...

[ZJChaser]

Originally Posted by shay2nak

I didn't know you guys are already using heatshields. What does Brent's intercooler look like?

Brents own setup is still stock.

[Thomasio]

Originally Posted by ZJChaser

Brents own setup is still stock.

That intercooler looks like a Cup intercooler... or did he just strip the finish off of the stock piece?

[Thomasio]

Re: the heat shield on mine... that's really just the template that I used, it was about Coke-can thick.

The head shield benefits from extending past the front and rear edges of the intercooler. If you think about radiant heat, it will travel line-of-sight from anything that is hotter to anything that is cooler, so a larger heat shield pays dividends.

[shay2nak]

that's what I'd guess. Maybe even a raised section of a couple inches front and back. remember that mspaint drawing I posted a while back? What's a good thickness? 3-5mm?

[Boothy]

Originally Posted by shay2nak

that's what I'd guess. Maybe even a raised section of a couple inches front and back. remember that mspaint drawing I posted a while back? What's a good thickness? 3-5mm?

I have just had an Ally heat shield made in 1.5mm thick, should be more than enough to stop radiant heat and does not weigh to much ;-)

cheers

Boothy